<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  
  <script>
    // 下面打印的结果是 ll 说法对吗

    const str = 'hello'
    console.log(str.substring(2,3)); // llo
  </script>
</body>
</html>